UNITED NATIONS (AP) — The United Nations is warning that the number of people inside Syria needing humanitarian aid could rise sharply from 2.5 million now to 4 million by early next year if the civil war grinds on at its current deadly pace.

John Ging, operations director for the U.N. humanitarian office, said the U.N. is also projecting that a failure to end the fighting will lead to an increase in the number of Syrians fleeing to neighboring countries, from almost 400,000 at present to around 700,000 in early 2013.

Ging spoke in an interview ahead of Friday’s fifth Syria Humanitarian Forum in Geneva where between 350 and 400 representatives of governments, international organizations and aid groups will hear reports on the sharply deteriorating humanitarian situation in Syria.

“People need to be aware of just how desperate the situation is inside Syria for the people there, how unbearable it is, and how they are suffering and falling into ever deeper despair and humanitarian need,” Ging said. “It’s just getting a lot worse very rapidly for the ordinary people.”

At the moment, he said, the U.N. and other aid organizations are only able to reach 1.5 million of the 2.5 million people in need of assistance inside Syria — and one of the reasons is funding.

Ging said the humanitarian program for Syrians still inside the country, and the program for Syrian refugees in camps in Turkey, Jordan, Lebanon and other neighboring countries, are both “seriously underfunded,” with donors providing less than 50 percent of the amount needed.

As of Nov. 2, the U.N. appeal for $348 million to provide food, water and other humanitarian aid for those inside Syria had received $157 million — just 45 percent of the requirement. Ging said about half the aid is being delivered to conflict areas and half to those who have fled to safer areas inside the country.

As of Oct. 23, the U.N. refugee agency said its appeal for $488 million to help Syrian refugees was only about a third funded.

“This is putting an unsustainable burden on first and foremost the neighboring states,” Ging said in the interview Wednesday before heading to Geneva. “There isn’t a fair burden sharing with those countries who have so generously opened their borders and allowed those hundreds of thousands of people to flee. They are carrying the lion’s share of the financial cost.”

Ging said a key message at Friday’s meeting will be an appeal for a broader base of donors to share the financial burden, especially to the wealthy Gulf states.

The big funders currently are the European Union, the United States, Britain, Germany, Russia, Norway, Australia, Canada, Sweden and Switzerland, he said.

There are no major donors from Muslim countries, but Ging said he hopes that will change since he is co-chairing Friday’s meeting with the EU, the Arab League and the Organization of Islamic Cooperation.

The U.N. will also be making “a big push and a big appeal to convert the rhetoric of concern for the plight of the Syrian people into more concerted and effective political action to end the conflict, because that is what is creating the humanitarian consequences,” Ging said.

Peter Maurer, head of the Geneva-based International Committee of the Red Cross, said Wednesday his organization can’t cope with some of Syria’s humanitarian needs despite its improved operations in the country because of the expanding conflict.

Activists say the 20-month civil war has killed more than 36,000 people and forced hundreds of thousands from their homes.